The present invention discloses improvements to the quick action clamp of U.S. Pat. No. 6,386,530 which is incorporated herein in its entirety by reference.
Squeeze operated clamps are well known. The related art uses an elongated plate to bind a bar at an angle to create a drive or locking action. A familiar application of this method is shown in British Patent 1555455 which shows a caulking gun device. A driving plate 41 and a locking plate 51 are fitted around a shaft. Each plate has a biasing spring also surrounding the shaft.
U.S. Pat. No. 4,926,722, 5,009,134 and 5,022,137 are some of a series to J. Sorensen et al covering a squeeze operated bar clamp. The '134 reference shows a retractable setscrew holding the jaw in place. A locking plate is positioned in front of a trigger handle. A compression spring surrounds the bar and presses a drive plate forward. The drive plate and drive spring are held in position by the bar. In FIG. 9 of '134 a locking plate is shown behind the trigger handle. U.S. Pat. No. 6,412,767 shows a variation of the Sorensen clamps with a removable jaw. The jaw is held to the bar by engaging a separate stop element of the bar. No new internal structures in the housing area are disclosed over the '137 or other references.
U.S. Pat. No. 5,005,449 shows a further version of a squeeze actuated clamp in which the trigger handle is parallel to the bar and the handle is squeezed toward the bar.
U.S. Pat. No. 5,161,787 shows in FIG. 3 a shaft driving apparatus. A two speed action is provided through the use of a flexible linkage 90 and a rigid linkage 75. The leverage from handle 34 depends upon the force required of bar 26. The bar moves the opposite direction from the handle motion. Compression spring 38 is surrounded at its non-moving end by ribs of the body structure. The other spring end which presses the drive plate is positioned only by the bar passing within the spring.
U.S. Pat. No. 5,853,168 shows a clamp similar to that of Sorensen except that the clamping jaws point down and the locking plate extends upward directly above the trigger handle. The drive and lock plates are positioned within the housing by a rib 31. The drive plate bias spring 22 is positioned in a similar manner to '787 above. As seen in FIG. 2 of '168 the front end of spring 22 is held in position only by bar 12.
U.S. Pat. No. 4,874,155 shows a C-clamp where locking plate release 13 faces rearward. The lock plate spring is positioned around the bar. A drive plate spring is mounted to a shaft separate from the bar. The bar moves in the opposite direction from the handle motion.
In U.S. Pat. Nos. 4,524,650 and 4,739,838, a varying speed lever mechanism for a screwdriver is disclosed. The levers include various sliding and pivoting linkages.
U.S. Pat. No. 669,282, from 1901, shows a jaw element movable along a bar. A setscrew contacts the bar to prevent such movement. U.S. Pat. No. 5,454,551 shows a jaw that is movable upon the bar by tilting the jaw.
In the clamping devices general design types are seen. One type is a C-clamp where the body of the tool is C shaped. The bar moves oppositely from the trigger handle mounted at the base of body. A caulking gun is also in this category. A second version is a bar clamp where the bar is drawn toward the body in the same direction as the handle is moved. The present invention is directed to the pistol grip bar clamp. In a pistol grip design a part of the housing body extends downward in parallel to a trigger handle such that the handle extends substantially perpendicular to the movable bar. The jaws may be above or below the bar in a pistol grip design. The mechanical limitations and requirements are different between a C clamp and a bar clamp.